1. Field of the Invention
The present invention relates generally to a fastening assembly, and more particularly to a fastening assembly used for reliably fastening a heat dissipation device to a printed circuit board.
2. Description of Related Art
With development in computer technology, electronic devices operate at high speed. It is well known that higher speed the electronic devices operate at, more heat they generate. If the heat is not dissipated duly, the stability of the operation of the electronic devices will be impacted severely. Generally, in order to ensure the electronic device to run normally, a heat dissipation device is used to dissipate the heat generated by the electronic device. Moreover, in order to keep the heat dissipation device intimately contacting the electronic device, a fastening assembly is usually desired to secure the heat dissipation device to the electronic device.
Nowadays, numerous fastening assemblies are used to secure the heat dissipation devices to the electronic devices located on respective printed circuit boards. Typically, a fastening assembly mainly formed of plastic is used. The fastening assembly comprises a lengthwise shaft, a head formed at an end of the shaft, a spring encircling the shaft and a retaining portion formed at an opposite end of the shaft for engaging with the printed circuit board. The retaining portion comprises a left flexible portion, a right flexible portion and a longitudinal groove defined between the two portions for providing a deforming space to the two portions. In assembly, the retaining portion of the fastening assembly is inserted into a through hole defined in the heat dissipation device and an aperture defined in the printed circuit board. Due to confine of the hole and the aperture, the left flexible portion and the right flexible portion are deformed toward each other in the groove, and then pass through the hole and the aperture. Thereafter, the left flexible portion and the right flexible portion are released to their original positions where they are free. Here, the heat dissipation device and the printed circuit board are sandwiched between the retaining portion and the spring with the retaining portion pressing against the printed circuit board upwardly and the spring pressing the heat dissipation device downwardly toward the printed circuit board. Thus, the heat dissipation device is secured to the electronic device. However, due to the fastening assembly being formed of plastic, the fastening assembly is prone to aging after being used for a long time. Then the retaining portion of the fastening assembly will become loosen due to aging and thus cannot secure the fastening assembly on the heat dissipation device firmly, causing an unreliable engagement between the heat dissipation device and the electronic device.
What is needed, therefore, is a fastening assembly which can overcome the above disadvantages.